The subject invention is directed to the art of measuring systems and, more particularly, to display devices such as gauges or the like for visual presentation of associated parameters.
Measuring systems including gauges of the type under consideration are commonly used in the automotive arts to display associated parameters derived from a motor vehicle such as, for example, vehicle speed, engine rotational speed in revolutions per minute, fuel tank levels, and other parameters. Typical analog display instruments include a movable indicator needle that is operated by means of an underlying control mechanism such as, for example, a stepping motor or a rotor coil. The indicator needle typically extends adjacent a graduated scale providing indicia of the value range of the parameters of interest. The rotor coil or stepping motor in the underlying measuring system control actuates motion of the movable indicator needle relative to the graduated scale for a visual presentation of the subject parameter.
In many known display systems, separate measuring systems are typically used for the display of each individual parameter. Each separate measuring system includes a set of connection contacts for supplying the respective signals to the measuring system from the corresponding parameters. Also, each measuring system typically includes a separate driven shaft provided in a housing or the like of the measuring system. The driven shaft is typically connected with an indicator needle which is moved relative to a graduated scale in a manner described above.
One problem exists, however, with respect to combination instruments of the type described above. Frequently, the desire to place the required number of measuring systems within the housing of a single combined gauge or instrument presents a space constraint problem. Often, it is desired to arrange the analog displays in close proximity to each other. However, the measuring systems that drive the analog displays often restrict the ability to do so.
It is therefore desirable to provide a measuring system such as an integrated automotive gauge mechanism for simultaneous visual display of associated parameters relating to the motor vehicle that is inexpensive, occupies a small space, and has the ability of displaying the status of a plurality of monitored parameters simultaneously.
The subject invention provides a compact dual integrated gauge mechanism for visual display of at least two associated parameters simultaneously. The gauge system includes first and second gear mechanisms. A first driven shaft adapted to carry an indicator needle or the like extends from a housing of the measuring gauge and includes a hollow opening extending therethrough. A second driven shaft extends from the housing and is arranged coaxially in the hollow opening of the first driven shaft. A free end of the second driven shaft extends beyond the free end of the first driven shaft. At least one first independently operable drive mechanism is connected with the first driven shaft through the first gear mechanism. Similarly, at least one second independently operable drive mechanism is connected with the second driven shaft through the second gear mechanism.
The coaxial arrangement of the two driven shafts extending from two respectively independently actuatable controls enables analog display of at least two parameters within an extremely small area. The present invention conserves on space both with respect to the display elements or the display scales as well as with respect to the measuring system.
In addition, the coaxial arrangement of the first and second driven shafts permits positioning of two indicator needles or hands in a stacked relationship and pivotable about a single axle point. It is to be appreciated that this arrangement of the indicator needles enabled by the present invention is extremely beneficial in certain instances such as, for example, in the representation of two or more parameters using a single round instrument layout.
In accordance with one aspect of the invention, the measuring system mechanism includes at least one first and one second independently activatable drive mechanism disposed in a single housing. Preferably, the housing comprises an upper component and an intermateable lower housing component. Preferably, each of the first and second drive mechanisms are identically formed resulting in the benefit of reduced manufacturing costs due mainly to the minimized part count in the overall measuring system mechanism. The invention is conducive to high volume industrial production resulting in significant cost savings.
In accordance with another aspect of the invention, the first and second drive mechanisms are disposed in the housing in a mutual inverted mirror image position relative to a virtual reflection plane passing through the housing. Preferably, each of the first and second drive mechanisms are substantially flat or very narrow. Accordingly, the mirror-inverted arrangement of the first an second drive mechanisms permits and extremely flat construction of the subject measuring instrument.
In accordance with yet another aspect of the invention, the first and second drive mechanisms are preferably respectively connected via an intermediate pinion to a drive pinion connection in a torsion-proof manner to each respective driven shaft. Accordingly, a gear unit is provided at minimal cost for transmitting the driving movements of the first and second drive mechanisms to the driven shafts.
In accordance with another aspect of the invention, the first driven shaft having a hollow opening extending therethrough is integrally formed with a first drive pinion. Preferably, the integral first drive pinion and first driven shaft is formed as an extrusion-molded plastic component.
In accordance with a still further aspect of the invention, a second pinion member is disposed on the second driven shaft in a manner to prevent relative axial and rotational movement therebetween. The lower extremity of the second driven shaft is positioned in the housing and rotatably received in a positioning recess formed by the first housing member. In addition, a support bridge member is provided in the housing for rotatably supporting the second driven shaft at a second point directly or in the area of a retainer collar formed by the second drive pinion. The driven shaft can be inserted onto a corresponding support pin in the lower half of the housing and locked or pressed together with the housing. The retainer bridge member thus permits simple assembly and support of the second driven shaft and of the second drive pinion.
In accordance with still yet further an aspect of the invention, the retainer bridge member is formed in a fashion to preferably simultaneously serve to axially locate a first intermediate pinion rotatably positioned within the housing between the first drive mechanism and the first driven shaft. To that end, the first intermediate pinion is preferably inserted on a support pin disposed in the bottom of the housing. Axial movement of the first intermediate pinion is limited by the underside of the support bridge member.
In accordance with a further aspect of the invention, the support bridge member includes a guide sleeve portion formed thereon for rotatably supporting the first drive pinion. The guide sleeve portion of the support bridge member includes an inner surface adapted to engage the first driven shaft. The first driven shaft extends through the guide sleeve portion of the support bridge member for guiding the first driven shaft through the opening formed in the first driven shaft. Preferably, the guide sleeve portion of the support bridge is formed in such a manner that it engages the hollow shaft portion of the first driven shaft over a sufficiently large axial region to provide stable support of the first driven shaft or the first drive pinion connected therewith.
In addition, the first driven shaft is rotatably supported in the upper portion of the housing with a centering collar provided on the top portion of the housing. The centering collar preferably is also functional to adapt the subject measuring system mechanism for mounting onto an associated support member such as an automotive dash board or the like.
In accordance with yet a further aspect of the invention, the housing cover is adapted to axially locate the first intermediate pinion which is preferably inserted upon a support pin disposed in the lower half of the housing. In this manner, by providing the support bridge member, combined with the top and bottom portions of the housing, the subject gauge mechanism is formed in an extremely simple and compact fashion and further, with a substantially flat overall construction.
Still other aspects, advantages, and benefits the invention will become apparent to those skilled in the art upon a reading and understanding of the following detailed description.